Amorphous and humidity caking: A review

Caking of products is a common and undesired phenomenon in food, chemical, pharmaceutical, and fertilizer industries which leads to extra cost and irregular quality. In general, caking processes could be identified as amorphous caking or humidity caking. In this review, history of studying caking, formation, methods, and prospects of these two caking processes are summarized and discussed. The relevant studies from the 1920 s to today are mentioned briefly. According to the different properties(i.e. hygrocapacity, hygrosensitivity, mechanical properties, and diffusion behavior) of amorphous powders and crystals, the conditions and mechanisms of amorphous and humidity caking are discussed. It is summarized that glass transition, moisture sorption, quantitative methods characterizing caking, accelerated caking tests, and simulation of caking behaviors are the main aspects that should be studied for a caking process. The methods for these five aspects are reviewed. Potential research points are proposed including caking of mixed particles, caking with phase transition or polymorph transition,non-homogenous caking, and simulation of caking.

Constructing 2D ultrathin graphene oxide membranes with supramolecular-assembled nano-adhesives for enhancing water stability

Atomic-thick two-dimensional(2D)graphene oxide(GO)has emerged as an ideal building block in developing ultrathin 2D membranes for separating substances.However,due to the negative charge of GO sheets when hydrated,electrostatic repulsion causes GO membranes to disintegrate easily in water,limiting their wide application in aqueous solutions.Here,we introduce and apply the concept of localized gluing by designing ultra-small supramolecular-assembled nanoparticles as nanoadhesives(NPA)to construct robust GO membranes with a thickness of only 24 nm.The supramolecular-assembled NPA were synthesized by cyclodextrin(CD)and tannic acid(TA)with a uniform size distribution of about 4.5 nm,and exposed surface pyrogallols that could strongly interact with GO sheets.The physical sizing of the NPA confines the interlayer spacing and maintains the nanochannel,while the natural molecular properties of the NPA enhance the connection between adjacent layers and inhibit swelling detachment.The fabricated ultrathin 2D membranes show a remarkable two times enhancement of water permeance over pristine GO membranes and exhibit excellent durability with record-breaking stability for 720 h immersion in water.This strategy provides meaningful insights into the design and fabrication of robust ultrathin membranes for practical application.

Cocrystal engineering:towards high-performance near-infrared organic phototransistors based on donor-acceptor charge transfer cocrystals

Near-infrared organic phototransistors have wide application prospects in many fields.The active materials with the high mobility and near-infrared response are critical to building high-performance near-infrared organic phototransistors,which are scarce at present.Herein,a new charge transfer cocrystal using 5,7-dihydroindolo[2,3-b]carbazole(5,7-ICZ)as the donor and 2,2’-(benzo[1,2-b:4,5-b’]dithiophene-4,8-diylidene)dimalononitrile(DTTCNQ)as the acceptor is properly designed and prepared in a stoichiometric ratio(D:A=1:1),which not only displays a high electron mobility of 0.15 cm^(2)V^(-1)s^(-1) and very low dark current,but also can serve as the active layer materials in the region of near-infrared detection due to the narrowed band gap and good charge transport properties.A high photosensitivity of 1.8×10^(4),the ultrahigh photoresponsivity of 2,923 A W-1and the high detectivity of 4.26×10^(11)Jones of the organic near-infrared phototransistors are obtained.

Tat-functionalized Ag-Fe_3O_4 nano-composites as tissue-penetrating vehicles for tumor magnetic targeting and drug delivery

In this paper, we prepared a dual functional system based on dextrin-coated silver nanoparticles which were further attached with iron oxide nanoparticles and cell penetrating peptide(Tat), producing Tat-modified Ag-Fe_3O_4 nanocomposites(Tat-FeAgNPs). To load drugs, an –SH containing linker, 3-mercaptopropanohydrazide, was designed and synthesized. It enabled the silver carriers to load and release doxorubicin(Dox) in a pH-sensitive pattern. The delivery efficiency of this system was assessed in vitro using MCF-7 cells, and in vivo using null BalB/c mice bearing MCF-7 xenograft tumors. Our results demonstrated that both Tat and externally applied magnetic field could promote cellular uptake and consequently the cytotoxicity of doxorubicin-loaded nanoparticles,with the IC_(50) of Tat-FeAgNP-Dox to be 0.63 mmol/L. The in vivo delivery efficiency of Tat-FeAgNP carrying Cy5 to the mouse tumor was analyzed using the in vivo optical imaging tests, in which TatFeAgNP-Cy5 yielded the most efficient accumulation in the tumor(6.772.4% ID of Tat-FeAgNPs).Anti-tumor assessment also demonstrated that Tat-FeAgNP-Dox displayed the most significant tumor-inhibiting effects and reduced the specific growth rate of tumor by 29.6%(P ? 0.009), which could be attributed to its superior performance in tumor drug delivery in comparison with the control nanovehicles.

Ultrasound-mediated targeted microbubbles： a new vehicle for cancer therapy

With the hope of overcoming the serious side effects, great endeavor has been made in tumor-targeted chemotherapy, and various drug delivery modalities and drug carriers have been made to decrease systemic toxicity caused by chemotherapeutic agents. Scientists from home and abroad focus on the research of targeted microbubbles contrast agent, and the use of the targeted ultrasound microbubble contrast agent can carry gene drugs and so on to the target tissue, as well as mediated tumor cell apoptosis and tumor microvascular thrombosis block, etc., thus plays the role of targeted therapy. Recent studies have elucidated the mechanisms of drug release and absorption, however, much work remains to be done in order to develop a successful and optimal system. In this review, we summarized the continuing efforts in under-standing the usage of the ultrasound triggered target microbubbles in cancer therapy, from release mechanism to preparation methods. The latest applications of ultra-sound-triggered targeted microbubbles in cancer therapy, especially in gene therapy and antiangiogenic cancer therapy were discussed. Moreover, we concluded that as a new technology, ultrasound-triggered targeted microbubbles used as drug carriers and imaging agents are still energetic and are very likely to be translated into clinic in the near future.

TCNQ-based organic cocrystal integrated red emission and n-type charge transport

Simultaneously realizing the optical and electrical properties of organic materials is always challenging.Herein,a convenient and promising strategy for designing organic materials with integrated optoelectronic properties based on cocrystal engineering has been put forward.By selecting the fluorene(Flu)and the 7,7′,8,8′-tetracyanoquinodimethane(TCNQ)as functional constituents,the Flu-TCNQ cocrystal prepared shows deep red emission at 702 nm,which is comparable to the commercialized red quantum dot.The highest electron mobility of organic field-effect transistor(OFET)based on Flu-TCNQ is 0.32 cm^(2)V^(−1)s^(−1).Spectroscopic analysis indicates that the intermolecular driving force contributing to the co-assembly of Flu-TCNQ is mainly charge transfer(CT)interaction,which leads to its different optoelectronic properties from constituents.

Immobilization of penicillin G acylase onto amino-modified silica hydrogel

Amino-modified silica hydrogel(N-MSHG)was prepared by a simple sol-gel processing via the cocondensation of commercial silica sol with 3-aminopropyltrieoxysilane.Penicillin G acylase(PGA),a model enzyme,was covalently immobilized onto the N-MSHG and then was used for the enzymatic synthesis of amoxicillin.The samples were characterized by Nitrogen sorption analysis,FT-IR and thermal gravimetric analysis(TGA).The results showed that the amino-modified gel was a mesoporous material with an average pore size of 12.64±0.17 nm.The immobilization process was efficient and the immobilized enzyme showed high catalytic efficiency.The yield of the synthesis of amoxicillin in aqueous media was 38%for 2.5 h.This sol-gel preparation is simple and shows prominent potential value in industrial processing.

The dehydration behavior and non-isothermal dehydration kinetics of donepezil hydrochloride monohydrate （Form I）

Powders of donepezil hydrochloride monohy- drate （Form I） underwent isomorphic dehydration, losing 3% w/w water between 90% and 10% relative humidity （RH） without changing its powder X-ray pattern. Below 10% RH, additional dehydration occurred in conjunction with a reversible phase transition between the monohy- drate state and a dehydrated state, with a 4.0% w/w loss to 0% RH. A combination of methods was used to understand the structural changes occurring during the desolvation process, including dynamic vapor sorption measurements, thermal analysis and powder X-ray diffraction. Form I showed the characteristics of the channel hydrate, whose non-isothermal dehydration behavior proceeds in two steps： （1） the loss of non-crystalline water adsorbed on the surface, and （2） the loss of one crystalline water in the channel. Dehydrated Form I is structurally similar to the monohydrate Form I. According to the heat of fusion and the crystal density criteria, the two crystal forms belonged to the univariant system, and the anhydrate （Form III） is stable. The dehydration kinetics was achieved from the TG-DTG curves by both the Achar method and the Coats- Redfern method with 15 frequently cited basic kinetic models. The dynamic dehydration processes for steps 1 and 2 were best expressed by the Zhuralev-Lesokin- Tempelman equation, suggesting a three-dimensional diffusion-controlled mechanism.

Developing macromolecular therapeutics:the future drug-of-choice

Macromolecular drugs including peptides,proteins,antibodies,polysaccharides and nucleic acids have been widely used for therapy of major diseases such as carcinoma and AIDS as well as cardiovascular and neurodegenerative disorders among other medical conditions.Due to their unmatched properties of high selectivity and efficiency,macromolecular drugs have been recognized as the drug-of-choice of the future.Since worldwide progress on macromolecular therapeutics still remains in the infant stage and is therefore wide open for equalground competition,R&D related to macromolecular drugs should be considered as the main point of focus in China in setting up its strategic plans in pharmaceutical development.In this article,research strategies and drug delivery approaches that should be adopted to enhance the therapeutic effects of macromolecular drugs are reviewed.In addition,comments concerning how to implement such strategies to excel from competition in this challenging research field,such as the design of innovative and highly effective delivery systems of macromolecular drugs with self-owned intellectual property rights,are provided.